Duplex telegraphy.



' I. KITSEE.

DUPLEX TELEGRAPHY.

APPLIOATION FILED APE.6, 1911. RENEWED .TAH.'13, 1914.

L 1,094,578. Patented Am. 28, 1914,

WITNESSES INVENTOR.

unrrnn STATES PATENT onnron. I

ISIDOR KITSE'E, F PHILADELPHIA, PENNSYLVANIA, ASSIGNOR TO AMERICAN TELE-PHONE AND TELEGRAPH COMPANY, NEW YORK. I

Specification of Letters Patent.

OF NEW YORK, N. Y., A CORPORATION OF DUPLEX TELEGRAPHY.

Patented Apr. 28, 1914.

Application filed April '6, 1911, Serial No; 619,299, Renewed January13, 1914. Serial No. 811,904.

To all whom it may concern -Be it known that I,,Is1n0n- Krrsnn, citizenof the United States, residing at Philadelphia, in the county otPhiladelphia and.

State of Pennsylvania, have invented certain new and useful Improvementsin Du plexTelegraphy, of whichf'thefollowing is a specification. Myinvention relates to an-iinprovement in duplex telegraphy. Itsbbject isto produce an efficient arrangement'tor duplexing' on'lines 'with' greatcapacity, such assubmarine cables, and has more special reference toduplex telegraphy in which the'in- 'f coming impulses are tobe receivedby devices adapted to actuate a local circuit.

My experiences have brought out the fact that if relays are employed asreceiving instr'uments in cable telegraphy, the inconr .ing currenthas'to be curbed for the pur- Z pose of eliminatingthe efle'ctfof themoving zero due to the capacity of the cable. s lhis curbing reducestheavailable energy to a great extent and, in practical working onsubmarinecables where the impressed voltage is limited, furtherre'ductionresults in a loss ofispeed; ln-working simplex, no furtherloss is entailed, but most of the cables are worked today with the.duplexing-bridge and in this system, a greater part of the arrivedcurrent is lost. The

two sides of the bridge have to be providedwith resistances, so as toforce part of the incoming current through the receiving device. To makea lar 'e percentage of the. m-

' coming energy available, it is best that these resistances should beof a high valuc'as compared with the receiving device in the cross wireof the bridge, but as the bridges at both terminals have to beelectrically alike, the great disadvantage arises that through such highresistances, the trans- 'm1tt1ng.current is cut down at the transmittingstation; and if, on the other hand, the resistances in the-bridge sidesare made low as compared with the resistance of the recelvlng device inthe cross w1re, then the.

incoming current passes to the great'estextent to earth-withoutaffecting the opera 9 tion of the receiving relay.

In my experiments, I have found that in simplex working (withoutemploy-ing- ,the'

bridge) it is best 'tohave two impedances ,l} the first one insertedhetiveenthe, cableand ground and'the second in shunt-to the fijrstimpedance may have a-very low resistance valuev even if the resistanceofthe receiving: device is comparatively; high. [In working over lineswith about'two million K. R, I had -good results with-an impedanceimpedance; and l have found thatthefirst placed between "the cable andground of i only thirtyohms resistance when the re ceiving device had aresistance of one thousand ohms. It has to be stated that thesecondimpedance had ahigher value than the first and was connected tothe first with the'interposition of a capacity. "In-my ex-' periments,this capacity had a value of,

twenty microfarads. v

For the purpose of adopting the arrangementsubstantially as outlined"and making available a greaterpart of the energy. in du-.

plexing, as is now possible, I have. recourse to arrangementssubstantially as illustrated in the accompanying drawing and describedin the specification.

' The drawing represents in diagrammatic view one terminal of aduplevsystem connected to the cable including transmitting and receivingorganism. I have here illustrated the transmitting organism as tocomprise means for keeping normally a current on. the cable and toenable the operator to transmit two impulsesof' opposite polaritytoreach manipulation of the key, as I' prefer in my system, to telegraphover the cable with Morse characters and transmit for each character apositive and negative impulse, but it is obvious that the transmit--ting arrangement may be changed to suit requirements.

In'tlns drawing; 1 is the. cable; 2 the bridge arrangement as'anentirety; 8 the transmitting arrangement as an entirety. Of the bridgearrangement, 2, 4 is an im pedanceinserted in one sideflof the bridgeand 5"th e impedance inserted in the second side of the bridge.

I 0; and b are the terminals of impedance 4; and a and b the terminalsofimpedancefi. Terminal apt impedanceA -is' connected through wire 6with the interposition ofthe condenser 7 to terminal 7) of impedance andterminal 7) of impedance 4 is connected through wire 8 with theinterposition of con- -.--.denser 9 to the terminal a of impedance 5.

Theimpedan'ce 11.is connected in shunt to thewires 6 and 8 throughcircuit wires 10. I l is a relayconnected-in shunt through circuit wires12, here shown with the interposition of condenser 13 to the impedance11. The condenser 9 i provided with means 29, condenser 7 with means 23and condenser 13 with means 24 to short circuit the same.

In my experiments, I have found that condenser 13 is not necessary forthe purpose of receiving good results and I have, therefore, shown thesame in the drawings as being short circuited through the switch. But Ihave found that condensers t) and T greatly facilitate the operation ofthe arrangement and I have, therefore, shown the shunts of thesecondensers being open.

The transmitting arrangement 3 comprises here the two batteries 18 and19; t he battery 18 being of double the electromotive force of thebattery 19. It is obvious that the required amount oi'dhdividlml cellsmay constitute the batteries 18 or 19, provided,.

however, that the battery "18 is double the clectroinotive force of thebatter 19.

20 is a shunt around battery 18 and 21 the key operating said shunt.'hen the key is open, a current flows from battery lSYovcr. the cable inthe direction of the unt'eathercd arrow and, when the key is closed, acurrent flows over the cable in the direction of the feathered arrow.The home impulses are neutralized in the bridge and do not affect theinner part of the bridge arrangement at all, but when an impulse fromthe far station arrives, the same has to travel through impedance 4 andwill, therefore, be felt in the shunt circuit including the impedance 11and the relay 14.

I have found that this arrangement is far superior to the arrangementwhere the re ceiving device is simply inserted in a cross wire of thebridge as is ractised today.

16 represents the arti cial line and 17 the ground.

Having now described my invention, what I claim as new and desire tosecure by Letters Patent is:-

1. Means to duplex lines with great capacity, said meai'is con'iprisinga bridge circuit, a resistance for each side of said bridge circuit, cr,circuits connecting the two terminals of the resistance of one bridgeside to the two terminals of the resistance of the second bridge side,an inductive resistance connected with one terminal to one of the crosscircuits and with the second terminal to the second of thecrosscircuits, a shunt for said indmrtivc resistance, a relay, saidrelay connected in said shunt circuit.

2. In a bridge for dnplexing lines with great capacity, an inductiveresistance for each side of said ln'idge, a condenser connecting oneterminal of the resistance of one bridge side with the opposite terminalof the resistance of the second bridge side, asecond condenserconnecting the other-terminal of the resistance of one bridge side withthe opposite terminal of the resistance of the second bridge side.

In a duplcxing bridge, an inductive re sistance for each side of saidbridge, two cross circuits, one cross circuit connecting the nearterminal of the resistance of one bridge side to the tar terminal of theresistanccof the second bridge side and the second cross circuitconnecting the near termina of the resistance of the second bridge sideto the tar terminal of the. resistance of the first bridge side.

4. In duplex telcgraphy, a bridge circuit, an inductive .resistance ineach side of said bridge circuit,'two cross wires connecting crosswisethe inductive resistances of both bridge sides, a shunt from said crosswires, the shunt connected with one terminal to one of said cross wiresand with the other terminal to the second of said wires. an in ductivcresistance for said shunt, a second shunt, a condenser in said secondshuin and a receiving device closing said shunt.

5. In duplex telcgraphy, meansato reduce the loss of the incomingimpulses due to the bridge circuit,, said means comprising inductiveresistances inserted in the sides of the bridge circuits. two crosscircuits connecting the two terminals of one inductive resistance to thetwo terminals of the other inductive resistance, a condenser in each ofsaid cross circuits. a relay. a circuit for said. relay, one terminal ofsaid circuit conne ted to one of said cross circuits. the ond terminalconnected to the second of said cro s circuits; 4

6. In duplex tclcgraplrv. a bridge r uit. an inductive resist ance "foreach side a lid bridge circuit, a"condenser connected with one terminalto one terminal of the inductive resistance of one bridge side and withthe ther terminal to the opposite terminal of the inductive resistanceof the second i bridge side, a second condenser, said second coir denserconnected with one terminal to the second terminal of the inductiveresistance .of the first bridge side and with the other terminal to theoppos te term nal of the inn ductivo resistance of the second bridgeside, an ind uctive resistance connected in shunt J0 said two condensersand a relay connected shunt to the last named inductive resistance.

Tu testiu'iony whereof T atlix nrv signature in presence of twowitnesses.

ISIDOR K ilSEE.

W'itncsscs Em'rn R. STILLEY, lllanr C. Snrrrr.

